Intracellular Concentrations Of MMP-9 In Peripheral Blood Leukocytes Increased In Patients With Acute Coronary Syndrome

Backgrounds: Atherosclerosis is a diffuse, systemic disease of the arterial network, and inflammation is a major role in all stages of atherosclerosis. Inflammatory cytokines involved in vascular inflammation stimulate the generation of endothelial adhesion molecules, proteases, and other mediators which may enter the circulation in soluble form. These primary cytokines also induce production of the messenger cytokine interleukin-6, which stimulates the liver to increase production of acute-phase reactants such as C-reactive protein. Plaque rupture and the ensuing thrombosis commonly cause acute coronary syndromes (ACS) . The shoulder region of plaques contain MMP-9, which is catalytically active and may thus contribute to the dysregulation of extracellular matrix that leads to plaque rupture. A lot of data support an important role for MMP-9 in several stages of atherosclerosis.Objective:Through observing the intracellular MMP-9 levels of peripheral blood leukocytes and the serum high sensitive C-reactive protein (hs-CRP) level in patients with acute coronary syndrome (ACS), and analyzing the relation between them,the aim of this study is to discuss the diagnosis value of intracellular MMP-9 to the plaque's vulnerability of ACS ,which will provide a fast and simple method for forecasting the plaque's vulnerability of ACS clinically.Methods:Twenty patients with acute coronary syndromes (ACS, n = 20) including 8 patients with unstable angina pectoris and 12 patients with acute myocardial infarction were studied, these patients were chosen according to the diagnosis criterion on acute coronary syndrome. Synchronously, 20 patients with stable angina pectoris (SA, n = 20) and individuals without cardiovascular disease (control, n = 20) chosen to be comparable groups. The sample was 5ml blood drawn out from the elbow vein of all patients be studied after admitted to hospital. Intracellular MMP-9 concentrations were measured in peripheral blood leukocytes by flow cytometry. The serum hs-CRP level were measured by ELISA methods,the difference of serum MMP-9 and hs-CRP level among groups was compared and correlation between them was analyzed. All data were analyzed by the statistical packages SPSS 12.0 for windows.Results:(1)Patients with ACS had a significantly higher levels of intracellular MMP-9 in peripheral blood leukocytes, represented by mean fluorescence intensity,(125.7±49.92 vs 51.60±18.99 ,11.26±13, P<0.01,P<0.01) , than those in patients with SA and patients without cardiovascular disease. But there were no different significance between patients with SA and patients without cardiovascular disease (P= 0. 20).And the positive percentage of cells containing MMP-9 in peripheral blood leukocytes also increased in patients with ACS .(2) The serum concentration of CRP in ACS group were significantly higher than those of SA group and control group (12.90±1.98 mg/L vs 4.33±1.98 mg/L , 3.73±1.68 mg/L, P < 0. 01, P < 0. 01),but there were no different significance between SA group and control group(P=0.53).(3) The serumal level of hs-CRP was correlated positively with the level of MMP-9 in ACS group (r=0.51,P=0.02).Conclusions:(1) The levels of intracellular MMP-9 increased in peripheral blood leukocytes in patients with ACS, measuring intracellular MMP-9 may be a convenient and efficient method to predict the vulnerability of AS plaque. (2) The level of hs-CRP was correlated positively with the level of intracellular MMP-9 in patients with ACS ,both the levels of hs-CRP and MMP-9 can increase in the inflammation.